The invention relates to a method for carrying out metallurgical or chemical processes in a shaft furnace by supplying electric energy by means of a plasma burner means penetrating the upper cover of the shaft furnace.
With known methods of this kind, or with conventional plasma melting furnaces, quite generally there exists the problem that the energy delivered by a plasma torch cannot be transmitted to the charging stock with satisfactory efficiency. When using diatomic plasma gases, the temperatures prevailing at the core of a plasma torch are around 15,000.degree. C., and when using monoatomic plasma gases the temperatures are up to 30,000.degree. C. Thus, a large part of the energy is given off by radiation. A substantial part of this radiation cannot be used for the high-temperature process or melting process, which furthermore also leads to a substantial thermal wear of the furnace lining.
Attempts have already been made at better utilizing the energy introduced by a plasma discharge by enlarging the cross-section of the discharge area. Thus, from U.S. Pat. No. 3,404,078, a method of producing a plasma arc is known, in which one of the electrodes is constituted by a fluidized bed of electrically conductive particles. Various materials may be introduced into the plasma region; the products resulting in the high temperature zone get into the fluidized bed and are cooled there. The method according to this U.S. patent thus is not suited for obtaining products in the molten state.
The invention aims at avoiding the difficulties described and has as its object to provide a method that is suited both for carrying out metallurgical processes and for chemical high-temperature reactions, in which a rapid melting and a quick reaction between the components of the charging stock is attained and in which the continuation of the method can be controlled in an improved manner.